Circuit breakers



Dec. 20, 1955 H. E. REICHERT Erm.

CIRCUIT BREAKERS Filed July 3o, 1952 XNVENTORS Howard E, Reicherland Freese.

ATTOR Y WITNESSES:

Gerold J.

United States Patent O CIRCUIT BREAKERS Howard E. Reichert and Gerald J. Freese, Beaver, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July so, 1952, serial No. 301,692

6 Claims. (Cl. 20o- 168) This invention relates to electrical devices in general and more particularly to terminal constructions for electrical devices such as circuit breakers.

An object of the invention is to provide a circuit interrupter having exposed terminals for connecting the circuit interrupters in an electrical circuit with a terminal cover acting as a guard for preventing accidental contact with a live terminal.

Another object of the invention is to provide a circuit interrupter having exposed terminals with a protective cover for the terminals which requires no separate means for fastening it in place.

Another object of the invention is to provide a circuit interrupter having exposed terminals with a snap-on terminal cover formed from a at sheet of insulating material and which requires no separate means for holding the cover in place on the housing of the interrupter.

The invention, both as to structure and operation together with additional objects and advantages thereof, will be best understood from the following detailed description thereof when read in connection with the accompanying drawing.

In said drawing:

Figure 1 is a perspective view showing one end portion of a circuit interrupter housing having exposed terminals and showing the protective cover for the terminals partly broken away for clearness.

Fig. 2 is a View showing the protective cover before it is mounted in place on the base of the interruptor.

Fig. 3 is a perspective view of the protective cover.

Referring to Fig. 1 of the drawing, the circuit breaker 9, a portion of which is shown in Fig. 1, comprises a housing including a base 11 and a cover 13 secured to the base by means of screws 15 (only one being shown). The circuit breaker may be of the type shown in U. S. Patent No. 2,458,151, issued to Hiller D. Dorfman and Gerald J. Freese January 4, 1949, and assigned to the assignee of the instant application. Only a portion of the breaker housing is shown and described herein. The cover 13 may be sealed to the base by a sealing compound 17 poured over the heads of the screws 15 to prevent tampering with the breaker mechanism and changing the calibration of the breaker.

The base 11 of the breaker is longer than the cover 13 providing projecting end portions 19, (only one being shown), for supporting the breaker terminals.

The projecting end portions of the base 11 have one or more recesses 21 therein, in each of which is mounted a terminal 23. The raised or projecting portions on the projecting end portions 19 of the base 11 between the terminals 23 and at the sides of the outer terminals form insulating barriers between adjacent terminals.

The terminals 23 are rectangular in shape and are mounted on the projecting ends 19 of the base 11 in the recesses 21 and are secured to conducting terminal strips 24, (only the ends being shown), for connecting the breaker in an electrical circuit. The terminals 23 are provided with terminal screws 26 which threadedly en- 2,727,956 Patented Dec. 20, 1955 ICC gage an opening through the conducting strip 24 and the upper portion of the terminal 23. Pivotally mounted on the lower ends of each of the screws 26 is a clamping member 28 so that upon rotation of the screw 26 the clamping member will move up and down in the terminal thus providing means whereby the end of a conducting cable 30 may be securely clamped to the terminal 23. By having the electrical terminals 23 on the end portions 19 of the base 11 which project beyond the ends of the cover 13, the electrical connections may be made to the terminals without breaking the seal and removing the cover 13.

It is, at times, necessary to make connectionsto the breaker terminals from an energized bus. Under such conditions, particularly when the circuit breakers are mounted end to end in a panelboard or switchboard, and because of the exposed terminals of the breakers, accidental contact may be made simultaneously with adjacent terminals. To prevent such accidents and possible serious or even fatal injury to the person working on the circuit breakers, there is provided a snap-on protective cover or guard for the terminals of the breaker.

The protective cover 27 is made from a flat strip of insulating material in the shape shown in Fig. 2. The blank shown in Fig. 2 is cut from a sheet of insulating material having some resiliency such, for example, as hard ber or a material having a cloth or tibrous base impregnated with a phenolic resin. The cover 27 has projections 29 along the bottom (Fig. 2) and projections 31 along the top. The cover is also provided with a top portion 38 having end portions 33. The blank is formed or bent along the line 37 as shown in Fig. 3 so that the projections 29 make a right or slightly obtuse angle with the main top portion 38 when the cover is removed from the breaker and is in its unstressed condition. The projections 29 are adapted to lit into slots 35 in the recesses 21 and the projections 31 are adapted to be snapped intov the recesses 21 under the end of breaker cover 13 as at 36 (Fig. 1). f

In order to place the protective cover 27 inpositi'on on the projecting end 19 of the base 11 the .projections 29- are inserted downwardly in the recesses 21 so that the projections 29 enter the slots 35 defined by the ends of the conducting strips 24 and the base 11, and the short projections 31 are snapped into the recesses 21 under the breaker cover 13. The downwardly projecting portions 29 are then bent at a right angle to the top portion 38 against the resiliency of the material which then holds the cover in position. When placed in position on the projecting end of the base 11 the main body of the terminal cover rests on the barriers 25 covering the tops of the recesses 21 and the projections 29 of the terminal cover close the ends of the recesses 21, thus completely enclosing the upper part of the terminals.

The provision of the protective cover eliminates or greatly reduces the possibility of a persons hand accidentally touching a live terminal, or of bringing a tool into simultaneous contact with the terminals of adjacent phases of the circuit. The protective cover is placed in position on the base without the use of tools and held in position without any separate fastening means such as screws or springs.

Having described the invention in accordance with the provisions of the patent statutes, it is to be understood that various changes and modications may be made in the structural details and arrangement of parts thereof without departing from some of the essential features of the invention.

We claim as our invention:

l. In a circuit interrupter comprising a housing of insulating material, barriers at the ends of said housing forming spaced recesses, a terminal mounted in each of circuit; a; separate-terminal.' guard mounted on; said -baririers andihavingspaced Vprojections thereon-extendinginto said recesses, means defining slots in said recesses for-receiving said 'projections andholding said-projections in'zpiace,y said separate terminal' guard being-bent toward said interrupterhousingy and having otherprojections thereon-V engaging portions-of saidV interrupter-'housing to4 firmly holdv said separateV terminal- -guard' inplace.

.3: In-y a circuitl interrupter: comprising an insulatinghousingincludingfabase and a.cover sealed'tosaid base,

said basehaving-at` least: one end` extending beyond-theupper: portion-of: said cover, barriers 'atsaid end1 of saidhousing formingrecesses between-them, terminals mounted; ini said.- recessesl to .permit connecting saidinterrupter ina an electrical; circuit. without removingl said interrupter coi/en a; snapon terminal guardmounted 'onf said barriem,` projectionslon said: terminali guardadaptedto beinserted: intoJ-said recesses for coverin'gthe ends of saidv recesses, ribs in said: recesses for'receiving said; projections toholdfsaidprojections iii-place, said terminalfguard-be bent toward sa'idf interrupter housing- 'atright angles taz-Saidfprojectionsand other projections on said termimail guardi adapted to beengaged. with portionsl of' saidinterrupten housing to-.hold' saidi terminal,v guard in place.

4; In; a.- circuitvinterrupter comprising a housing' includnt base and-a cover -sealedtoisaid base, saidibase-haiv'-4 ing-r-atalcastrf'one end :extending: beyond; saidcover, barriers omsaidnendfoff--said' base forming recesses-between them,

terminals mountedin saidrecesses topermit connectingsaid interrupter in an electrical circuit without` removingsaid"intem'1pter'cover, anda-u snap-onf terminal* guard mounted oni-saidi vend of-Y said-:f-base extendingv-'b'eyondlsaid cover, projections on said terminal guard adapted to be inserted. inv said` recesses. for coveringthe ends of-saidrecesses, means in said base for receiving said projections, said terminal guard being bent toward said cover at right angles to said projections, and other projections on said terminal guard adapted to engage a portion of said sealed interrupter cover to holdA said-- terminal guard in place without the use of any separate fastening device.

5. In a circuit interrupter comprising a housing including-a base and akcover-sealed to said base, said base,hav ing at least one end extending-beyond the upper4 portion of said cover, barriers; atfsaidAendofvsaidihousing forming recesses between themte rminalsmounted in said re cesses to permit connecting said-interrupter in an electri- 6. In a circuit interrupter comprising a housing'includ-t ing al base-andiacover4 sealed-to said base, Ybarriers* at' the end off saidA housing forming arecessV between them, a

terminal mounted -insaid: recess to permit; connectingV said.y interrupter in an electrical circuitwithout removing-said" seal'edfcover, and al snap-on terminal guard*` mounted on said barriers, -a projection on said terminal, guard adaptedV to lne-,mounted insaid'- recess to cover theK end. of saidA recess, means-defining-a slot-'in' said base` for' receiving,l said projection; said# terminal guard 'afterfsaid projection isinserted in said-'slot-being bent towardfsaid'housngat right angles--to-said-projection, and 'another projection on saidl terminal guard--adaptedlto engagea portion of( said' interrupterhousing -to holdA saidf terminal guardin p lace; 

